Drug-Drug interactions are identified through a combination of clinical observation, scientific research, pharmacological knowledge, and the use of specialized tools. In clinical practice, healthcare providers assess the risk of interactions by reviewing a patient’s complete medication list, including prescription drugs, over-the-counter products, and supplements. Pharmacists and physicians rely on drug databases, electronic prescribing systems, and clinical decision support tools that automatically flag known interactions based on current evidence. Scientific identification of DDIs occurs during drug development, through in vitro and in vivo studies, clinical trials, and post-marketing surveillance.